1. Field of the Invention
The present invention relates to a driving method of a liquid crystal sub-pixel. More particularly, the present invention relates to a driving method of a liquid crystal sub-pixel capable of reducing image sticking problem.
2. Description of Related Art
Due to the superior characteristics of high picture quality, good space utilization, low power consumption, and radiation free, liquid crystal displays has gradually become the mainstream products of display device in the market. Inevitably, charged impurities or ions exist in liquid crystal molecules of the liquid crystal display panel. After a long time operation, distribution of charged impurities or ions is gradually changed and results in deterioration of display quality of the liquid crystal display panel. Specifically, during a long time operation, charged impurities or ions may separate in accordance with polarity thereof After charged impurities or ions are separated in accordance with polarity thereof, the LC voltage VLC applied to the liquid crystal layer is reduced by the charged impurities or ions. Accordingly, variation of LC voltage VLC applied to the liquid crystal layer occurs. The phenomenon is so-call screen effect. Additionally, after charged impurities or ions separated in accordance with polarity thereof, a parasitic potential is generated within the liquid crystal bulk panel and the optimum voltage level of common electrode may vary (V-com shift phenomenon).
Since charged impurities or ions in the liquid crystal layer lead to screen effect and V-com shift phenomenon, image sticking problem (or surface-type image sticking problem) may occur. Accordingly, display quality of the liquid crystal display panel is deteriorated. In order to reduce image sticking problem resulted from charged impurities or ions, more reliable liquid crystal materials or modified fabrication processes are currently adopted to reduce quantity of charged impurities or ions. In addition, image sticking problem may also reduced by modified driving method of the liquid crystal display panel. However, image sticking problem can not significantly reduced by the above-mentioned solutions.